Preorder sales have not been "overwhelming" for the 5C, a U.S. wireless carrier source told Reuters. The phone comes in blue, green, pink, yellow and white and starts at $99 with a contract in the U.S. The pricier 5S phone begins at $199 with a contract.

Remembering Steve Jobs

One of the new features that comes with Apple's new iOS is Airdrop, which lets users share photos, videos, and contacts by clicking share and selecting another iOS 7 user from their contacts list. All of the transfers are encrypted and items can be sent using Wi-Fi or Bluetooth, according to MailOnline.

There is also a revamped Notification Center and the addition of a Control Center, which can be opened by swiping from the bottom of the screen, letting users tweak different settings.

The software update also boasts of improvements to the Compass app, the way photos are organized, and a flashlight app called Torch has also been added.

Reviewers have been calling the latest iOS incarnation a huge success, with Apple's Senior Vice President of Engineering, Craig Federighi, predicting that anyone installing iOS 7 will feel as if they're "getting an all-new device."